1. Field of the Invention
The present invention relates to a safety control device and a safety control system, which maintain a drive instrument, such as a servo or an inverter, in a safe condition in a control room, a machine room, or the like.
2. Description of the Background Art
A drive instrument using power electronics, such as a servo or an inverter, is used in a fan or pump in a factory or the like, an elevator, a machine room in a building, a drive portion of a manufacturing device, or the like. In recent years, there is a growing need for the safety of this kind of drive instrument. Therefore, JP-A-2004-282368 proposes a technology wherein an image of a hazardous region is taken in a workplace in a factory, and a difference between frames of the image of the hazardous region is detected, thereby detecting an entrance of a moving object into the hazardous region. Also, in JP-A-2004-276154, an image of a monitoring object region is taken by a camera installed at a height overlooking the monitoring object region including a hazard source. Further, an entrance of an operator into the monitoring object region is detected by this imaging.
However, the heretofore known safety instruments heretofore described are such that when an operator enters an area in which a hazard source, such as a robot or a power source, exists, the hazard source is stopped in order to ensure the safety of the operator even though the operator is far enough away from the hazard source. Also, in particular, when the hazard source is a moving object such as a robot, it is necessary, in order to ensure the safety of the operator, to divide an area using a safety fence or the like between the hazard source and the operator so as to prevent the operator's entrance. Therefore, the heretofore known technology has the problem of an increase in working area or a decrease in operating rate due to stopping the robot, power source, or the like.